A plastic panel structure fabricated by way of a blow-molding process is shown and described. More specifically, a substantially hollow and lightweight blow-molded plastic panel structure is disclosed with a structural geometry that increases the load capacity of the panel structure and further resists creeping, sagging and warpage under high load conditions.
Plastic panels and blow-molded panels are known in the art and may be combined with support structures to form a complete shelving or storage unit. The consumer appeal to plastic shelving systems includes two competing interests. Specifically, consumers prefer that the panel structures and shelving systems be lightweight but consumers also demand that the shelving systems be strong and durable or, in other words, have relatively high load capacities. Low cost is also a general concern.
However, current designs that are lightweight and are fabricated from a minimum of plastic material, thereby lowering the cost of the article, can suffer from the drawback of lower load capacity and may also suffer from sagging, creeping and warpage under high load conditions, especially when used as a horizontal shelf. Specifically, heavy loads placed on a lightweight panel structure can cause creeping, sagging or warping due to the panel structure""s ability to withstand the load due to the insufficient wall thickness and insufficient weight of the panel structure. As a result, the panel structure can creep, sag or warp thereby interfering with the panel structures inability to interact with the other components of the system, namely the support components. Further, lightweight blow-molded panel structures have been known to fail under typical higher load conditions thereby causing frustration to the user and possible damage to the goods stored thereon.
In an attempt to the increase the load capacity of plastic blow-molded panel structures, manufacturers have resorted to making the panel structures heavier, thereby adding wall thickness and using more material, thereby driving up the costs. Other solutions include additional separate bracket components to improve the product performance. Using additional materials increases the cost and the weight which is not preferred. Further, using additional bracket or bracing components adds to the complexity of the shelving systems which makes them difficult to assemble and results in additional competition with more complex metal or wooden shelving systems.
Therefore, there is a need for an improved lightweight plastic blow-molded panel structure and accompanying system which is lightweight, inexpensive, easy to use and which is capable of withstanding high loads without creeping, sagging or warping when used in a horizontal or vertical position.
In satisfaction of the aforenoted needs, a plastic panel structure is disclosed which comprises a first panel and a second panel spaced apart from the first panel. The second panel comprises a plurality of lateral beams extending upward from the second panel and towards the first panel to connect the second panel to the first panel. Each beam defines a lateral slot through the second panel and towards the first panel.
In a refinement, the second panel further comprises a plurality of transverse ribs with each transverse rib extending through one of the lateral slots.
In a refinement, the first panel further comprises a plurality of lateral grooves with each groove of the first panel being in alignment with one of the lateral beams of the second panel.
In a further refinement, the first panel is arched upward away from the second panel while the second panel is flat or substantially flat.
In another refinement, the first panel is connected to the second panel by a front wall and a rear wall wherein the front wall is arched. In yet another refinement, the first panel is connected to the second panel by two opposing sidewalls, both of which are connected to the front and rear walls.
In another refinement, each transverse rib has an average lateral width. The average lateral width of the transverse ribs disposed toward a lateral center of the first panel is greater than an average lateral width of the transverse ribs disposed closer to the front or rear walls. As a result, the ribs disposed toward the center of the panel structure are thicker and stronger than those disposed towards the front and rear ends of the panel structure.
In yet another refinement, each transverse rib has a bottom edge that extends from one side of its respective lateral slot to an opposite side thereof and each bottom edge of each rib is arched upwards towards the first panel to minimize material consumption.
In another related refinement, each transverse rib has a top edge that extends from one side of its respective lateral slot to the opposite side thereof. The top edge of each rib being arched downward, away from the first panel to minimize material consumption.
Preferably, the panel structures are made from a blow-molding process.